1. Field of the Invention
The present invention relates to an apparatus for preventing disorder in sheet alignment in a sheet stack-up section for stacking up sheets transported successively by a transporting conveyor at its outlet portion.
2. Description of the Prior Art
Heretofore, as the above-described type of apparatus for preventing disorder in sheet alignment, an apparatus disclosed in Laid-Open Japanese Utility Model No. 59-192069 (1984) has been known. Explaining a general construction of this known apparatus, a brush having a large width wider than the maximum sheet width and densely planted with hair over its entire width is disposed along a sheet passageway above an inlet of a sheet stack-up section, and also at an outlet of a transporting conveyor is provided a press roll adapted to press the sheet on the transporting conveyor.
In this heretofore known apparatus for preventing disorder in sheet alignment, a sheet is forcibly ejected by pinching rotation of the transporting conveyor and the press roll, brush hair in a region corresponding to a sheet width is pushed out, while the brush hair remaining on the opposite sides of the sheet has a function of side guides upon transporting the sheet to the stack-up section, and thereby upon stacking up the sheets, it was intended that lateral slip of the sheet can be prevented by the remaining brush hair. However, if a rigidity of the brush hair is made too high, then the edges of the sheets would be deformed or cracked, also a resistive force against the sheet is increased, and hence the position of stacking would become unstable. On the contrary, if the rigidity of the brush hair is made too low, then the function of the brushes on the opposite side of the sheet of restraining a lateral slipping phenomenon of the sheet would be weakened. Thus, it was impossible to make a same brush have both the functions which are inconsistent with each other, and so, the known apparatus could not be said to be an apparatus of surely preventing disorder in sheet alignment.